The present disclosure herein relates to a semiconductor device and, more particularly, to a semiconductor memory device.
Generally, semiconductor memory devices may store digital data. As electronic industries and semiconductor industries develop to a high degree, demand for high integration of the semiconductor memory devices has gradually increased. With the development of electronic equipment such as laptop computers, cellular phones, digital cameras, or MP3 players, the semiconductor memory devices have been required to store larger amounts of data.
Semiconductor memory devices may be highly integrated by shortening a minimum line width of fine patterns forming devices. By two-dimensionally shortening the minimum line width of the fine patterns, it is possible to integrate many memory cells in a limited area. However, there is a limit to methods of shortening the minimum line width due to various factors (for example, limit of photolithography process). For this reason, developments have actively been made on alternative methods to highly integrate semiconductor memory devices.